(a) Field of the Invention
The present invention relates to an in-line system for a liquid crystal display, and a method of fabricating a liquid crystal display using the same.
(b) Description of the Related Art
Generally, the fabrication of a liquid crystal display involves processes of fabricating an array substrate where wiring line patterns and switching circuits (in the case of an active matrix type) are formed on a glass substrate, a liquid crystal display cell process where alignment treatment, spacer formation and injection of a liquid crystal between the array substrate and an opposing substrate are made, and a module process where attachment of driver ICs and mounting of a backlight are made.
A plurality of liquid crystal display cell regions are simultaneously formed at a mother glass in the array substrate fabrication process. The plurality of liquid crystal display cell regions are severed from each other to form separate display units through cutting in the liquid crystal display cell process.
In the liquid crystal display cell process, a vacuum injection or a drop injection may be made to fill the cells with liquid crystal.
With the vacuum injection, an alignment film is coated onto the substrates to align the liquid crystal molecules, and then surface-treated. Spacers are formed at one of the substrates to maintain the cell gap in a constant manner, and a sealer with a liquid crystal inlet hole is printed around the substrates. The substrates are then aligned and assembled with each other through a hot press process with a thermal-hardening sealer. After grooves are formed at the substrates per a panel unit through scribing, the substrates are severed from each other through impact cutting. The respective panels are put into a vacuum vessel such that the liquid crystal inlet hole of the sealer is dipped into a liquid crystal. In this way, the liquid crystal is injected into the liquid crystal display cell. Finally, the liquid crystal inlet hole is sealed such that the injected liquid crystal is contained.
With the drop injection, an alignment film is coated onto the substrates, and then surface-treated. Spacers are formed at one of the substrates. After a sealer is formed around one of the substrates in the shape of a closed curve, a liquid crystal is dropped onto the substrate. The two substrates are aligned, and assembled with each other by way of the sealer. Finally, the sealer is hardened.
In the case of drop injection, as liquid crystal is contained within the liquid crystal display cell while being severed into unit cells through scribing, the characteristic of the liquid crystal can deteriorate from loss of alignment force of the alignment films and due to the impact to the substrates, and this can result in poor display characteristics. To prevent such a problem, the substrate severing may be completely made at the groove formation process based on scribing by penetrating the cutting blade through the substrates. In this case, the stress applied to the substrates at the cutting becomes increased. Consequently, the possibility of deteriorating the display characteristic of the liquid crystal display cell is increased and production yield is decreased.
It is an object of the present invention to provide a system and method of fabricating a liquid crystal display which prevents deterioration of the display characteristic at the severing of the substrates into unit cells, thereby enhancing production yield.
An in-line system for fabricating a liquid crystal display is provided, the in-line system comprising a spacer dispersing unit for dispersing spacers onto at least one of first and second substrates with a plurality of liquid crystal display cell regions; a sealer coating unit for coating a sealer onto the first substrate; a liquid crystal injection unit for dropping liquid crystal onto the first substrate coated with the sealer; an assembly unit for assembling the first substrate with the second substrate; a sealer hardening unit for hardening the sealer interposed between the first and the second substrate to thereby join the first and the second substrate; and a substrate cutting unit for cutting the first and the second substrates along cutting lines through illuminating a laser beam along the cutting lines such that the first and the second substrates are severed into the liquid crystal display cell regions.
Preferably, the substrate cutting unit comprises a laser for pre-heating the first and the second substrates along the cutting lines; a laser transporter for fixing or transporting the laser; and a cooling agent spraying unit for cooling the pre-heated first and second substrates along the cutting lines. The substrate cutting unit further comprises a substrate transporter for fixing, rotating or transporting the first and the second substrates. The cooling agent spraying unit is mounted on the laser transporter.
According to a preferred embodiment of the present invention, the spacer dispersing unit, the sealer coating unit, the liquid crystal injection unit, the assembly unit, the sealer hardening unit and the substrate cutting unit are designed to be in-line. The in-line system further comprising first and second preliminary alignment units for aligning the first and the second substrates with each other before the assembling, and a heat treatment unit for heat-treating the liquid crystal.
A method is provided for fabricating a liquid crystal display, the method comprising the steps of dispersing spacers onto at least one of first and second substrates with a plurality of liquid crystal display cell regions; coating a sealer onto the first substrate; dropping a liquid crystal onto the first substrate; assembling the first and the second substrates to join with each other; hardening the sealer interposed between the first and the second substrates; and cutting the first and the second substrates along cutting lines using a laser such that the first and the second substrates are severed into a plurality of liquid crystal display cell regions.
The step of cutting the first and the second substrates further comprises the steps of pre-heating the first and the second substrates along the cutting lines through illuminating a laser beam along the cutting lines; cooling the first and the second substrates along the cutting lines through spraying a cooling agent along the cutting lines to thereby form a crack; and propagating the crack along the cutting lines.
According to another preferred embodiment of the present invention, an in-line system for fabricating a liquid crystal display comprises means for dispersing spacers between first and second substrates; means for joining the first and second substrates to form a gap; means for injecting liquid crystal onto the gap; and means for cutting the first and the second substrates along cutting lines such that the first and the second substrates are severed into the liquid crystal display cell regions.
The means for cutting comprises a laser for pre-heating the first and the second substrates along the cutting lines; a laser transporter for fixing or transporting the laser; and a cooling agent spraying unit for cooling the pre-heated first and second substrates along the cutting lines.
The means for joining comprises a sealer coating unit and a sealer hardening unit, the sealer coating unit for coating at least one of the first and second substrates with a sealer and the sealer hardening unit for hardening the sealer.